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Stockholders Equity - Schedule of Reserved Shares of Common Stock for Issuance (Details) - shares	Mar. 31, 2024	Dec. 31, 2023
Class Of Stock [Line Items]
Reserved shares of common stock for issuance	22,851,751	18,357,134
2020 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Reserved shares of common stock for issuance	1,621,594
Option To Purchase Common Stock
Class Of Stock [Line Items]
Reserved shares of common stock for issuance	8,594,001	10,439,751
Unvested Restricted Stock
Class Of Stock [Line Items]
Reserved shares of common stock for issuance	1,564,941	3,254,863
Stock Available For Grant \| 2020 Stock Option and Grant Plan
Class Of Stock [Line Items]
Reserved shares of common stock for issuance	12,692,809	4,182,461
Stock Available For Issuance \| 2020 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Reserved shares of common stock for issuance	1,621,594	480,059

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

Nature of the Business - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2024	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Percentage of workforce reduction	95.00%
Net losses attributable to common stockholders		$ (30,299)	$ (41,183)
Accumulated deficit		(686,492)		$ (656,193)
Cash, cash equivalents and short-term investments		$ 140,500

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

Net Loss per Share (Tables)

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Computation Of Basic And Diluted Net Loss Per Share Attributable To Common Stockholders

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company:


	Three Months Ended March 31,
(in thousands, except share and per share data)	2024			2023
Numerator:
Net loss – basic and diluted	$	(30,299	)	$	(41,183	)
Denominator:
Weighted-average common shares outstanding – basic and diluted		114,690,726			93,303,672
Net loss per share – basic and diluted	$	(0.26	)	$	(0.44	)

Potential Dilutive Securities Excluded From Computation Of Diluted Net Loss Per Share Attributable To Common Stockholders

Based on the amounts outstanding at March 31, 2024 and 2023, the Company excluded the following potential shares of common stock from the computation of diluted net loss per share attributable to common stockholders for the three months ended March 31, 2024 and 2023, because including them would have had an anti-dilutive effect. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same.


	March 31,
	2024		2023
Options to purchase common stock		8,594,001		10,753,342
Unvested restricted stock		1,564,941		3,675,716

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reserved shares of common stock for issuance	22,851,751		18,357,134
Stock-based compensation expense	$ 5,034	$ 10,029
Accelerated units	601,115
Accelerating recognition cost	$ 100
Reversal of stock-based compensation expense	3,500
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	(274)	3,423
Reversal of stock-based compensation expense	1,900
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	5,308	6,606
Reversal of stock-based compensation expense	1,600
Restricted Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation cost	$ 12,300
Weighted average period of cost expected to be recognized	1 year 10 months 24 days
Total fair value of restricted stock vested	$ 500	$ 1,600
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average period of cost expected to be recognized	1 year 7 months 17 days
Weighted average grant-date fair value of stock options granted		$ 5.18
Unrecognized stock-based compensation expenses	$ 19,400
Number of options, granted	0
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock issuable upon exercise of outstanding options	64,042
Reserved shares of common stock for issuance	0
2018 Equity Incentive Plan \| Restricted Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted	6,616,772
2020 Stock Option and Grant Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock issuable upon exercise of outstanding options	8,529,959
2020 Stock Option and Grant Plan \| Restricted Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted	5,356,510
2020 Stock Option and Grant Plan \| Stock Available For Grant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reserved shares of common stock for issuance	12,692,809		4,182,461
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reserved shares of common stock for issuance	1,621,594
Purchase of common stock under the employee stock purchase plan	0
Stock-based compensation expense	$ 0	$ 100

Nature of the Business

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of the Business

1. Nature of the Business

AlloVir, Inc. (“AlloVir” or “the Company”, formerly known as ViraCyte, Inc.) is a cell therapy company developing highly innovative allogeneic T cell therapies to treat and prevent devastating viral diseases. The Company’s innovative and proprietary virus-specific T cell, or VST, therapy platform allows AlloVir to generate off-the-shelf VSTs designed to restore immunity in patients with T cell deficiencies who are at risk from the life-threatening consequences of viral diseases. There is an urgent medical need for therapies to treat a large number of patients suffering from viral diseases who currently have limited or no treatment options. The Company’s platform includes three innovative, allogeneic, off-the-shelf VST therapy candidates targeting 11 different devastating viruses. The Company’s lead product candidate, posoleucel (previously referred to as Viralym-M or ALVR105), is a multi-VST therapy that targets six viruses: adenovirus (“AdV”), BK virus (“BKV”), cytomegalovirus (“CMV”), Epstein-Barr virus (“EBV”), human herpesvirus 6 (“HHV-6”) and JC virus (“JCV”).

In December 2023, the Company announced the discontinuation of three Phase 3 registrational trials of posoleucel following separate, pre-planned Data Safety Monitoring Board (“DSMB”), futility analyses that concluded the studies were unlikely to meet their primary endpoints. Specifically, the Company discontinued a multicenter, randomized, double-blind, placebo-controlled Phase 3 trial comparing posoleucel to placebo for the prevention of infection or disease due to AdV, BKV, CMV, EBV, HHV-6, or JCV in high-risk adult and pediatric patients after undergoing an allogeneic hematopoietic stem cell transplant. The Company also discontinued two multicenter, randomized, double-blind, placebo-controlled Phase 3 trials of posoleucel – one for the treatment of virus-associated hemorrhagic cystitis and the second for the treatment of adenovirus infection – both after allogeneic hematopoietic cell transplant.

In December 2023, the Company also announced that it would review the detailed datasets from those Phase 3 trials and launch a comprehensive review of strategic alternatives focused on maximizing stockholder value, including, but not limited to, a merger, sale, divestiture of assets, licensing, or other strategic transaction. The Company expects to devote substantial time and resources to exploring strategic alternatives that the board of directors believes will maximize stockholder value. Despite devoting significant efforts to identify and evaluate potential strategic alternatives, there can be no assurance that this strategic review process will result in us pursuing any transaction or that any transaction, if pursued, will be completed on attractive terms or at all. The Company has not set a timetable for completion of this strategic review process, and the board of directors has not approved a definitive course of action. Additionally, there can be no assurances that any particular course of action, business arrangement or transaction, or series of transactions, will be pursued, successfully consummated or lead to increased stockholder value, or that the Company will make any cash distributions to our stockholders. In connection with the evaluation of strategic alternatives and in order maximize capital preservation, the Company has implemented a plan to reduce our workforce by approximately 95%. This workforce reduction plan was approved in January 2024, and took place primarily during the first quarter of 2024 and was substantially completed by April 15, 2024.

The Company’s pipeline includes additional investigational VST therapies that may benefit high-risk individuals. ALVR106 is the Company’s second off-the-shelf, multi-VST product candidate targeting devastating respiratory diseases caused by human metapneumovirus (“hMPV”), influenza, parainfluenza virus (“PIV”) and respiratory syncytial virus (“RSV”). A Phase 1b/2 proof of concept (“POC”) clinical study of ALVR106 has completed enrollment of patients in Part A of the trial. The Company has paused development of ALVR106, including discontinuing the trial pending the outcome of the Company’s review of strategic alternatives. Preclinical and IND-enabling studies of ALVR107 to treat and cure hepatitis B were completed in 2022 to support advancement into a POC study. Clinical development of ALVR107 has been paused pending the outcome of the Company’s review of strategic alternatives.

Going Concern

In accordance with Accounting Standards Update (“ASU”) 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), the Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the condensed consolidated financial statements are issued.

Since its inception and until recently, the Company devoted substantially all of its resources to recruiting personnel, developing its technology platform and advancing its pipeline of product candidates through discovery, preclinical and clinical trials, acquiring and manufacturing clinical trial materials and maintaining and building its intellectual property portfolio. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, success of clinical trials, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Should the Company resume development of its product candidates, the product candidates will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval, prior to commercialization.

Through March 31, 2024, the Company has funded its operations primarily with proceeds received from the sale of common stock, research grants, and from the sale of preferred stock. The Company has incurred recurring losses since its inception, including net losses attributable to common stockholders of $30.3 million and $41.2 million for the three months ended March 31, 2024 and 2023, respectively. In addition, at March 31, 2024, the Company had an accumulated deficit of $686.5 million. The Company expects to continue to generate operating losses for the foreseeable future.

The Company has incurred and expects to continue to incur costs and expenditures in connection with the process of evaluating strategic alternatives. There can be no assurance, however, that the Company will be able to successfully consummate any particular strategic transaction. The process of evaluating strategic options has been and may continue to be costly, time-consuming and complex and the Company may incur significant costs related to this continued evaluation, such as legal, accounting and advisory fees and expenses and other related charges.

Based on current projections, the Company believes that its $140.5 million of cash, cash equivalents and short-term investments held at March 31, 2024 will be sufficient to fund planned operations for at least twelve months from the date that these condensed consolidated financial statements are available to be issued. However, due to the consideration of certain qualitative factors, including the discontinuation of all clinical trials and research activities, as well as the Company’s workforce reduction plan, management has concluded there is substantial doubt regarding the Company’s ability to continue as a going concern for more than twelve months from the date that the condensed consolidated financial statements are available to be issued. These financial statements do not include any adjustments that might result from the outcome of this uncertainty. Should the Company resume the development of product candidates, it would need to obtain substantial additional funding in connection with continuing operations, particularly as the Company resumes its preclinical activities and clinical trials for its product candidates. There can be no assurance that the Company will be able to obtain sufficient capital to cover its costs on acceptable terms, if at all.

ElevateBio, LLC – Related Party

On September 17, 2018, the Company executed a Series A2 Preferred Stock Purchase Agreement ("Series A2 Agreement") with ElevateBio, LLC ("ElevateBio") and ElevateBio was a purchaser in our registered direct offering in July 2022. ElevateBio, through its diverse platform of technologies to support cell and gene therapy products and expertise, provides drug development and manufacturing services. As a result of ElevateBio’s purchase of our Series A2 Preferred Stock, which converted to common stock upon completion of our IPO, and as a result of ElevateBio’s participation in the July 2022 registered direct offering, ElevateBio acquired an ownership interest in the Company. The Chief Financial Officer of ElevateBio currently serves in a similar management role with AlloVir. In May 2021, Diana M. Brainard, M.D. succeeded David Hallal, ElevateBio’s Chief Executive Officer, as the Company’s Chief Executive Officer. Mr. Hallal currently serves as Executive Chairman of the Company’s board of directors. Vikas Sinha, our President and Chief Financial Officer, also serves as the Chief Financial Officer of ElevateBio. In addition to Mr. Hallal and Mr. Sinha, Morana Jovan-Embiricos, a director of the Company’s board of directors, also serves as a director of the board of directors of ElevateBio.

Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2024

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consisted of the following:


(in thousands)	March 31, 2024		December 31, 2023
Employee compensation and benefits	$	2,200	$	3,809
Professional fees		464		435
Research and development		1,665		2,442
Process development and manufacturing costs		—		2,367
Other		267		1,033
Total accrued expenses	$	4,596	$	10,086

Employee compensation and benefits includes $1.7 million of restructuring liability (see Note 13).

Restructuring Costs - Details of Restructuring Liability Included in Accrued Expenses (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Restructuring and Related Activities [Abstract]
Restructuring charges	$ 9,464
Cash payments	(7,756)
Balance	$ 1,708

Restructuring Costs - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2024	Mar. 31, 2024
Restructuring Cost and Reserve [Line Items]
Percentage of workforce reduction	95.00%
Restructuring charges		$ 9,464

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

Leases

3 Months Ended

Mar. 31, 2024

Leases [Abstract]

Leases

5. Leases

Operating leases

Development and Manufacturing Services Agreement (“DMS Agreement”) with Third-Party Supplier

In October 2022, the Company entered into a Statement of Work (“SOW”) under the DMS Agreement (“2022 SOW under the DMS Agreement”) with a third-party supplier. The 2022 SOW under the DMS Agreement contained an embedded lease for a dedicated manufacturing suite for the manufacture of AlloVir’s products at the facility because the Company directs how and for what purpose the suite is used and obtains substantially all of the economic benefit of the suite. At inception of the lease, it was determined that, in exchange for this dedicated manufacturing suite, AlloVir will pay the supplier a monthly fixed suite utilization fee, fixed batch payments and other related fixed costs, totaling $16.3 million over the 2.25 year lease term ending in December 2024. As part of the arrangement, there were also variable costs for materials, non-fixed batch payments, testing, storage, knowledge and tech transfer and other common area maintenance fees that were not included in the measurement of the lease liability. The lease of the facility was determined to be classified as an operating lease and commenced in October 2022, the point at which the suite was substantially complete and available for use by the Company. Accordingly, at inception, the Company recorded a right-of-use asset and lease liability of $14.7 million.

In December 2023, the Company issued a notice of termination of the DMS Agreement effective June 2024, or 190 days from the third-party supplier’s receipt of the notice. Management concluded that the notice of termination constituted a lease reassessment under ASC 842 as the Company was granted the option of such termination at the onset of the DMS Agreement and it was previously determined to be reasonably certain of not being exercised. As a result, the remaining lease term was shortened and the Company recorded a $4.9 million reduction to the right-of-use asset and lease liability in December 2023.

In February 2024, the Company entered into a new SOW (“2024 SOW under the DMS Agreement”) that terminated the 2022 SOW under the DMS Agreement with a third-party supplier, resulting in a lease remeasurement under ASC 842. The right-of-use asset was previously impaired and thus as a result of the liability remeasurement, the Company recorded a $5.6 million gain to reduce the lease liability in February 2024. As of March 31, 2024, the Company has paid all remaining lease obligations under the DMS Agreement.

Waltham Leases

In September 2021, the Company entered into a lease agreement with BP Bay Colony LLC and a sublease with AMAG Pharmaceuticals Inc. for the lease of property in Waltham, Massachusetts (collectively, the “Waltham leases”). The space identified under the Waltham leases is intended for general office space, research and development, laboratory use, and light manufacturing. The Waltham leases are classified as operating leases and commenced in September 2021. At the inception date, the Company recorded a ROU asset and lease liability of $6.0 million for the lease and a ROU asset and lease liability of $17.3 million for the sublease based on a July 30, 2030 end date for the Waltham leases. As part of the arrangement, there were also variable costs for common area maintenance fees that were not included in the measurement of the lease liability. The agreement also provided a $3.1 million tenant improvement allowance. The Company utilized $0.9 million of the tenant improvement allowance. The Company has the option to renew the leased space for an additional one time period of five years with written notice from the Company. As of March 31, 2024, the Company has no reasonable certainty that this option to extend will be exercised.

Impairment of Lease Right-of-Use Assets

As a result of the December 2023 announcement of the discontinuation of the Company’s three Phase 3 registrational trials, a comprehensive review of strategic alternatives, and the December 2023 notice of termination of the DMS Agreement, the Company determined that there was a triggering event for impairment. The Company determined that the operating lease right-of-use assets were not recoverable as the carrying value exceeded the anticipated future cash flows on an undiscounted basis. To measure the impairment, the Company determined the fair value of the operating lease right-of-use assets based on estimated subleasing scenarios, which represent the highest and best use of the right-of-use assets. This fair value assessment utilized market participant assumptions, including the anticipated amount and timing of potential sublease payments using current real estate trends and market conditions. As a result, an impairment charge was calculated by reducing the carrying amount of the operating lease right-of-use assets to their estimated fair value, which was determined by discounting the estimated future cash flows by applying a rate that a market participant would require in assuming the risks associated with those cash flows. In December 2023, the Company recorded an impairment loss of $16.6 million to the operating lease right-of-use assets. No impairment losses were recorded during the three months ended March 31, 2024 and 2023, respectively. As of March 31, 2024, the remaining right-of-use asset balance is $2.1 million, which relates to the Waltham leases.

Maturities of operating lease liabilities at March 31, 2024 are as follows (in thousands):


2024 (remaining 9 months)		2,358
2025		3,219
2026		3,298
2027		3,376
2028		3,455
Thereafter		5,824
Total lease payments		21,530
Less: interest		3,188
Total lease liability	$	18,342
Lease liability – current	$	2,295
Lease liability – long-term	$	16,047

Total lease costs were $0.4 million and $2.6 million for the three months ended March 31, 2024 and 2023, respectively. Cash paid for operating leases was $3.8 million and $2.1 million for the three months ended March 31, 2024 and 2023, respectively. The Company’s total variable lease costs, such as materials, non-fixed batch payments, testing, storage, knowledge and tech transfer, and other common area maintenance fees, related to the operating leases was $0.1 million and $0.1 million for the three months ended March 31, 2024 and 2023, respectively. The weighted average remaining lease term was 6.33 years and 4.70 years at March 31, 2024 and December 31, 2023, respectively. The weighted average discount rate was 5.00% and 5.95% at March 31, 2024 and December 31, 2023, respectively.

Stock-Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Number of Options Outstanding, Beginning Balance	10,439,751
Number of Options, Forfeited	(1,845,750)
Number of Options Outstanding, Ending Balance	8,594,001	10,439,751
Options vested and exercisable at March 31, 2024	5,972,960
Weighted Average Exercise Price, Options outstanding as of January 1, 2024	$ 13.81
Weighted Average Exercise Price, Forfeited	8.61
Weighted Average Exercise Price, Options outstanding at March 31, 2024	14.93	$ 13.81
Weighted Average Exercise Price, Options vested and exercisable at March 31, 2024	$ 16.44
Weighted Average Contractual Life (in years), Options outstanding	7 years 6 months 14 days	7 years 11 months 12 days
Weighted Average Contractual Life (in years), Options vested and exercisable at March 31, 2024	7 years 3 months 14 days

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Short-Term Investments - Summary of Amortized Cost and Estimated Fair Value of Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 54,495	$ 93,749
Unrealized Gains	4	73
Unrealized Losses	(8)
Fair Value	54,491	93,822
U.S. Government Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	54,495	93,749
Unrealized Gains	4	73
Unrealized Losses	(8)
Fair Value	$ 54,491	$ 93,822

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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-Name Accounting Standards Codification
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-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

+ Details

Accrued Expenses

3 Months Ended

Mar. 31, 2024

Payables and Accruals [Abstract]

Accrued Expenses

6. Accrued Expenses

Accrued expenses consisted of the following:


(in thousands)	March 31, 2024		December 31, 2023
Employee compensation and benefits	$	2,200	$	3,809
Professional fees		464		435
Research and development		1,665		2,442
Process development and manufacturing costs		—		2,367
Other		267		1,033
Total accrued expenses	$	4,596	$	10,086

Employee compensation and benefits includes $1.7 million of restructuring liability (see Note 13).

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net loss	$ (30,299)	$ (41,183)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		86
Non-cash lease expense	80	461
Non-cash gain on lease termination	(5,583)
Accretion of short-term investment discounts	(745)	(729)
Stock-based compensation expense	5,034	10,029
Changes in operating assets and liabilities:
Interest receivable	26	(87)
Prepaid expenses and other current assets and prepaid expenses to related party	2,715	(333)
Other assets	122	122
Income tax payable		2
Accounts payable, accrued expenses, other liabilities and amount due to related party	(15,730)	(486)
Net cash used in operating activities	(44,380)	(32,118)
Cash flows from investing activities
Purchase of short-term investments		(11,756)
Maturities of short-term investments	40,000	53,480
Net cash provided by (used in) investing activities	40,000	41,724
Cash flows from financing activities
Net (decrease) increase in cash, cash equivalents, and restricted cash	(4,380)	9,606
Cash, cash equivalents, and restricted cash at beginning of period	90,973	106,944
Cash, cash equivalents, and restricted cash at end of period	86,593	116,550
Non-cash investing and financing activities
Unrealized gain (loss) on available-for-sale securities	(76)	167
Supplemental disclosure of cash flows
Cash and cash equivalents	86,039	115,698
Restricted cash	554	852
Total cash, cash equivalents, and restricted cash	$ 86,593	$ 116,550

Stockholder's Equity

3 Months Ended

Mar. 31, 2024

Equity [Abstract]

Stockholder's Equity

7. Stockholder’s Equity

On May 15, 2023, the Company filed a certificate of amendment to its amended and restated certificate of incorporation authorizing the Company to issue up to 300,000,000 shares of common stock at a par value of $0.0001 per share and 10,000,000 shares of preferred stock at a par value of $0.0001 per share. There were no shares of preferred stock issued or outstanding at March 31, 2024 and December 31, 2023.

On June 21, 2023, the Company entered into an underwriting agreement with J.P. Morgan Securities LLC, Morgan Stanley & Co. LLC and BoFA Securities, Inc., as the representatives of the several underwriters (the “Underwriters”) relating to an underwritten public offering of 20,000,000 shares of its common stock at a public offering price of $3.75 per share, resulting in net proceeds of $70.2 million after deducting underwriting discounts and commissions of $4.5 million and offering costs of $0.3 million. Under the terms of the underwriting agreement, the Company granted the Underwriters an option, exercisable for 30 days, to purchase up to an additional 3,000,000 shares of its common stock at the same price per share as the shares, less underwriting discounts and commissions. On July 21, 2023, the Underwriters option expired.

The Company has reserved shares of common stock for issuance as follows:


	March 31, 2024		December 31, 2023
Options to purchase common stock		8,594,001		10,439,751
Unvested restricted stock		1,564,941		3,254,863
Stock available for grant under the 2020 Stock Option and Grant Plan		12,692,809		4,182,461
Stock available for issuance under the 2020 Employee Stock Purchase Plan	1,621,594			480,059
Total		22,851,751		18,357,134

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
-Section 50
-Paragraph 13
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-Publisher FASB
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+ Details

Leases - Summary of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Leases [Abstract]
2024 (remaining 9 months)	$ 2,358
2025	3,219
2026	3,298
2027	3,376
2028	3,455
Thereafter	5,824
Total lease payments	21,530
Less: interest	3,188
Total lease liability	18,342
Lease liability - current	2,295	$ 10,781
Lease liability - long-term	$ 16,047	$ 16,648

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2023, and notes thereto, which are included in the Company’s Annual Report on Form 10-K that was filed with the Securities and Exchange Commission (the “SEC”) on March 15, 2024. Since the date of those financial statements, there have been no material changes to the Company’s significant accounting policies except as described below.

Restructuring Costs

The Company records costs and liabilities associated with exit and disposal activities in accordance with ASC 420, Exit or Disposal Cost Obligations (ASC 420). Such costs are based on estimates of fair value in the period liabilities are incurred. Given the short duration of when the liability is incurred to when it is paid, there is no significant difference between fair value and the amount paid. Costs are expensed at the date the entity notifies the employee, unless the employee must provide future service, in which case the benefits are expensed ratably over the future service period. The Company evaluates and adjusts these costs as appropriate for changes in circumstances as additional information becomes available. Please refer to Note 13 for further information regarding restructuring costs.

Interim Financial Information

The accompanying condensed consolidated balance sheet at March 31, 2024, and the condensed consolidated statements of operations and comprehensive loss, statements of changes in stockholders’ equity for the three months ended March 31, 2024 and 2023 and the condensed consolidated statements of cash flows for the three months ended March 31, 2024 and 2023 are unaudited. The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair

presentation of the Company’s financial position at March 31, 2024 and the results of its operations for the three months ended March 31, 2024 and 2023 and its cash flows for the three months ended March 31, 2024 and 2023. The financial data and other information disclosed in these notes related to the three months ended March 31, 2024 and 2023 are also unaudited. The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024 or for any other subsequent interim period.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”), or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s condensed consolidated financial statements upon adoption. Under the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), the Company meets the definition of an emerging growth company and has elected the extended transition period for complying with certain new or revised accounting standards pursuant to Section 107(b) of the JOBS Act.

Since December 31, 2023, there have been no new accounting pronouncements adopted by the Company or issued by FASB that are applicable to the Company, except as noted below.

Recently Issued Accounting Pronouncements Not Yet Adopted

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires disclosure of incremental segment information on an interim and annual basis. This ASU is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal periods beginning after December 15, 2024, and requires retrospective application to all prior periods presented in the financial statements. The adoption of this standard is not expected to have a material impact on the Company’s condensed consolidated financial statements and related disclosures.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires public companies, on an annual basis, to provide disclosure of specific categories in the rate reconciliation, as well as disclosure of income taxes paid disaggregated by jurisdiction. This ASU is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The adoption of this standard is not expected to have a material impact on the Company’s condensed consolidated financial statements and related disclosures.

Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 5,034	$ 10,029
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	(274)	3,423
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 5,308	$ 6,606

Net Loss per Share - Computation Of Basic And Diluted Net Loss Per Share Attributable To Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net loss - basic and diluted	$ (30,299)	$ (41,183)
Denominator:
Weighted-average common shares outstanding - basic	114,690,726	93,303,672
Weighted-average common shares outstanding - diluted	114,690,726	93,303,672
Net loss per share - basic	$ (0.26)	$ (0.44)
Net loss per share - diluted	$ (0.26)	$ (0.44)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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+ Details

- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders.

+ References + Details

Leases (Tables)

3 Months Ended

Mar. 31, 2024

Leases [Abstract]

Summary of Maturities Operating Leases Liabilities

Maturities of operating lease liabilities at March 31, 2024 are as follows (in thousands):


2024 (remaining 9 months)		2,358
2025		3,219
2026		3,298
2027		3,376
2028		3,455
Thereafter		5,824
Total lease payments		21,530
Less: interest		3,188
Total lease liability	$	18,342
Lease liability – current	$	2,295
Lease liability – long-term	$	16,047

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2024
Accounting Policies [Abstract]
Restructuring Costs	Restructuring Costs The Company records costs and liabilities associated with exit and disposal activities in accordance with ASC 420, Exit or Disposal Cost Obligations (ASC 420). Such costs are based on estimates of fair value in the period liabilities are incurred. Given the short duration of when the liability is incurred to when it is paid, there is no significant difference between fair value and the amount paid. Costs are expensed at the date the entity notifies the employee, unless the employee must provide future service, in which case the benefits are expensed ratably over the future service period. The Company evaluates and adjusts these costs as appropriate for changes in circumstances as additional information becomes available. Please refer to Note 13 for further information regarding restructuring costs.
Interim Financial Information	Interim Financial Information The accompanying condensed consolidated balance sheet at March 31, 2024, and the condensed consolidated statements of operations and comprehensive loss, statements of changes in stockholders’ equity for the three months ended March 31, 2024 and 2023 and the condensed consolidated statements of cash flows for the three months ended March 31, 2024 and 2023 are unaudited. The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair presentation of the Company’s financial position at March 31, 2024 and the results of its operations for the three months ended March 31, 2024 and 2023 and its cash flows for the three months ended March 31, 2024 and 2023. The financial data and other information disclosed in these notes related to the three months ended March 31, 2024 and 2023 are also unaudited. The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024 or for any other subsequent interim period.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”), or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s condensed consolidated financial statements upon adoption. Under the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), the Company meets the definition of an emerging growth company and has elected the extended transition period for complying with certain new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. Since December 31, 2023, there have been no new accounting pronouncements adopted by the Company or issued by FASB that are applicable to the Company, except as noted below.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires disclosure of incremental segment information on an interim and annual basis. This ASU is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal periods beginning after December 15, 2024, and requires retrospective application to all prior periods presented in the financial statements. The adoption of this standard is not expected to have a material impact on the Company’s condensed consolidated financial statements and related disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires public companies, on an annual basis, to provide disclosure of specific categories in the rate reconciliation, as well as disclosure of income taxes paid disaggregated by jurisdiction. This ASU is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The adoption of this standard is not expected to have a material impact on the Company’s condensed consolidated financial statements and related disclosures.

Leases - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended
	Feb. 29, 2024	Dec. 31, 2023	Oct. 31, 2022	Sep. 30, 2021	Mar. 31, 2024	Mar. 31, 2023
Leases [Line Items]
ROU asset		$ 2,187			$ 2,107
Lease liability					18,342
Gain on termination of lease					5,583
Operating lease costs					400	$ 2,600
Impairment loss to operating lease right-of-use assets		$ 16,600			0	0
Remaining right-of-use asset balance					2,100
Cash paid for operating lease					3,800	2,100
Variable lease costs					$ 100	$ 100
Operating lease, weighted average remaining lease term		4 years 8 months 12 days			6 years 3 months 29 days
Operating lease, weighted average discount rate, percent		5.95%			5.00%
Waltham Leases
Leases [Line Items]
Expiration date				Jul. 30, 2030
Operating lease, existence of option to extend				true
Lease, option to extend					The Company has the option to renew the leased space for an additional one time period of five years with written notice from the Company. As of March 31, 2024, the Company has no reasonable certainty that this option to extend will be exercised.
Tenant improvement allowance to be reimbursed				$ 3,100	$ 900
Lease commencement month and year				2021-09
Additional one time lease period				5 years
New Lease Agreement with BP Bay Colony LLC
Leases [Line Items]
ROU asset				$ 6,000
Lease liability				6,000
Sublease with AMAG Pharmaceuticals
Leases [Line Items]
ROU asset				17,300
Lease liability				$ 17,300
2022 SOW Under the DMS Agreement
Leases [Line Items]
Lease expiration month and year			2024-12
ROU asset			$ 14,700
Lease liability			14,700
Utilization fee			$ 16,300
Lessee operating lease, lease term including renewal option			2 years 3 months
Reduction to right-of-use asset and lease liability		$ 4,900
2024 SOW Under the DMS Agreement
Leases [Line Items]
Gain on termination of lease	$ 5,600

Fair Value Measurements

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Fair Value Measurements

4. Fair Value Measurements

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis:


	March 31, 2024
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market fund	$	66,161					$	66,161
Totals	$	66,161	$	—	$	—	$	66,161
Short-term investments:
U.S. government treasury securities	$	54,491					$	54,491
Totals	$	54,491	$	—	$	—	$	54,491


	December 31, 2023
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market fund	$	23,854	$	—	$	—	$	23,854
Totals	$	23,854	$	—	$	—	$	23,854
Short-term investments:
U.S. government treasury securities		93,822		—		—	$	93,822
Totals	$	93,822	$	—	$	—	$	93,822

During the three months ended March 31, 2024 and the year ended December 31, 2023, there were no transfers between levels. The Company classifies its money market fund and U.S. government treasury securities as Level 1 assets under the fair value hierarchy, as these assets have been valued using quoted market prices in active markets without any valuation adjustment.

The carrying amounts of prepaid expenses and other current assets, prepaid expenses to related party, accounts payable, amount due to related party and accrued expenses approximate their fair values due to the short-term nature of these assets and liabilities.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Stock-Based Compensation - Schedule of Estimated Fair Value Weighted-Average Assumptions Using Black-Scholes Option-Pricing Model (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares
Share-Based Payment Arrangement [Abstract]
Expected term (in years)	6 years 1 month 9 days
Expected volatility	94.50%
Risk-free interest rate	3.46%
Expected dividend yield	0.00%
Fair value of common stock	$ 6.63

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating expenses:
Research and development	$ 12,173	$ 30,718
General and administrative	10,662	12,513
Restructuring costs	9,464
Total operating expenses	32,299	43,231
Loss from operations	(32,299)	(43,231)
Total other income (loss), net:
Interest income	1,246	1,325
Other income (loss), net	754	723
Net loss	$ (30,299)	$ (41,183)
Net loss per share - basic	$ (0.26)	$ (0.44)
Net loss per share - diluted	$ (0.26)	$ (0.44)
Weighted-average common shares outstanding - basic	114,690,726	93,303,672
Weighted-average common shares outstanding - diluted	114,690,726	93,303,672
Comprehensive loss:
Net Income (Loss)	$ (30,299)	$ (41,183)
Other comprehensive income (loss), net of tax:
Unrealized (loss) gain on available-for-sale securities	(76)	167
Total other comprehensive income (loss)	(76)	167
Comprehensive loss	$ (30,375)	$ (41,016)

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis:


	March 31, 2024
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market fund	$	66,161					$	66,161
Totals	$	66,161	$	—	$	—	$	66,161
Short-term investments:
U.S. government treasury securities	$	54,491					$	54,491
Totals	$	54,491	$	—	$	—	$	54,491


	December 31, 2023
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market fund	$	23,854	$	—	$	—	$	23,854
Totals	$	23,854	$	—	$	—	$	23,854
Short-term investments:
U.S. government treasury securities		93,822		—		—	$	93,822
Totals	$	93,822	$	—	$	—	$	93,822

Restructuring Costs

3 Months Ended

Mar. 31, 2024

Restructuring and Related Activities [Abstract]

Restructuring Costs

13. Restructuring Costs

In January 2024, the Company’s board of directors approved a RIF of approximately 95% of the Company’s employee base in order to reduce costs and preserve capital in light of the announcement on December 22, 2023 that the Company is discontinuing its three global Phase 3 posoleucel studies. The Company communicated the RIF to affected employees in January 2024.

The RIF was primarily completed during the first quarter of 2024 and was substantially completed by April 15, 2024. As a result of these actions, the Company recorded restructuring costs of $9.5 million, consisting primarily of employee severance, continuing healthcare benefits and other employee-related costs. Restructuring costs associated with one-time termination benefits were recorded pursuant to ASC 420. The Company expects cash payments related to the restructuring costs to be substantially complete by the second quarter of 2024.

The following table presents the details of the Company’s restructuring liability, which is included in accrued expenses on the consolidated balance sheet at March 31, 2024 as follows:


(in thousands)	Restructuring Liability
Balance at December 31, 2023	$	—
Restructuring charges		9,464
Cash payments		(7,756	)
Balance at March 31, 2024	$	1,708

Stock-Based Compensation - Summary of Restricted Common Stock Activity (Details) - Restricted Common Stock	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of Shares
Number of Shares, Unvested at January 1, 2024 \| shares	3,254,863
Number of Shares, Forfeited \| shares	(957,148)
Number of Shares, Vested \| shares	(732,774)
Number of Shares, Unvested at March 31, 2024 \| shares	1,564,941
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Unvested at January 1, 2024 \| $ / shares	$ 8.73
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	8.13
Weighted Average Grant Date Fair Value, Vested \| $ / shares	8.12
Weighted Average Grant Date Fair Value, Unvested at March 31, 2024 \| $ / shares	$ 9.37

Accrued Expenses - Additional Information (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Payables and Accruals [Abstract]
Restructuring liability	$ 1,708

Short-Term Investments

3 Months Ended

Mar. 31, 2024

Investments, Debt and Equity Securities [Abstract]

Short-Term Investments

3. Short-Term Investments

The following tables summarize the amortized cost and estimated fair value of the Company’s U.S. government treasury securities and marketable securities, which are considered to be available-for-sale investments and are included in short-term investments on the consolidated balance sheets:


	March 31, 2024
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. government treasury securities	$	54,495	$	4	$	(8	)	$	54,491
Totals	$	54,495	$	4	$	(8	)	$	54,491


	December 31, 2023
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. government treasury securities		93,749		73		—	$	93,822
Totals	$	93,749	$	73	$	—	$	93,822

Certain short-term debt securities with original maturities of less than three months are included in cash and cash equivalents on the consolidated balance sheets and are not included in the tables above. The Company holds debt securities of companies with high credit quality and has determined that there was no material change in the credit risk of any of its debt securities. At March 31, 2024 and December 31, 2023, all investments had contractual maturities within one year.

Restructuring Costs (Tables)

3 Months Ended

Mar. 31, 2024

Restructuring and Related Activities [Abstract]

Details of Restructuring Liability Included in Accrued Expenses

The following table presents the details of the Company’s restructuring liability, which is included in accrued expenses on the consolidated balance sheet at March 31, 2024 as follows:


(in thousands)	Restructuring Liability
Balance at December 31, 2023	$	—
Restructuring charges		9,464
Cash payments		(7,756	)
Balance at March 31, 2024	$	1,708

Commitments and Contingencies

3 Months Ended

Mar. 31, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

11. Commitments and Contingencies

Leases

The Company entered into a lease agreement and a sublease agreement for the lease of property in Waltham, Massachusetts (see Note 5).

Legal Proceedings

From time to time, in the ordinary course of business, the Company is subject to litigation and regulatory examinations as well as information gathering requests, inquiries and investigations. On January 19, 2024, a purported stockholder of the Company filed a lawsuit, captioned Zerbato v. AlloVir, Inc. et al., No. 1:24-cv-10152 (D. Mass.), in Massachusetts federal court against the Company and two of its officers purportedly on behalf of a putative class of stockholders consisting of persons who purchased or otherwise acquired Company securities between March 22, 2022 and December 21, 2023, inclusive. The complaint purports to assert claims under Section 10(b) and 20(a) of the Securities Act of 1934, as amended, and the related regulations, alleging that the defendants made false and misleading statements and omissions to investors relating to the Company’s three Phase 3 studies of posoleucel. The complaint seeks, among other things, damages, prejudgment and post-judgment interest, and attorneys’ fees, expert fees and other costs. On April 16, 2024, the Court appointed stockholders Harry Levin and Julio Maurice Bueno as lead plaintiffs and their counsel as lead counsel in the action. On April 22, 2024, the parties filed a stipulation and proposed order setting forth an agreed-upon schedule for the filing of an amended complaint and motion to dismiss briefing. The Court has not yet ruled on that stipulation. The Company intends to vigorously defend against the lawsuit. As the outcome is not presently determinable, any loss is neither probable nor reasonably estimable.

Purchase and Other Obligations

We enter into contracts in the normal course of business with CROs and other third-party vendors for clinical trials and testing and manufacturing services, which can contain purchase commitments or other noncancelable obligations. Most contracts do not contain minimum purchase commitments and are cancellable by us upon written notice. Payments due upon cancellation consist of payments for services provided or expenses incurred, including non-cancelable obligations of services provided up to one year after the date of cancellation. The amount and timing of such payments are not known.

We may incur potential contingent payments upon our achievement of clinical, regulatory and commercial milestones, as applicable, or we may be required to make royalty payments under license and grant agreements we have entered into with various entities pursuant to which we have in-licensed certain intellectual property. Due to the uncertainty of the achievement and timing of the events requiring payment under these agreements, the amounts to be paid by us are not fixed or determinable at this time (see Note 8 in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 15, 2024).

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 86,039	$ 90,121
Short-term investments	54,491	93,822
Interest receivable	181	206
Prepaid expenses and other current assets	771	3,486
Total current assets	141,482	187,635
Restricted cash	554	852
Other assets		122
Operating lease right-of-use assets	2,107	2,187
Total assets	144,143	190,796
Current liabilities:
Accounts payable	765	6,761
Accrued expenses	4,596	10,086
Operating lease liability, current	2,295	10,781
Total current liabilities	7,656	28,367
Operating lease liability, long term	16,047	16,648
Total liabilities	23,703	45,015
Stockholders’ equity:
Preferred stock, $0.0001 par value: 10,000,000 shares authorized at March 31, 2024 and December 31, 2023, respectively; 0 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively
Common stock, $0.0001 par value: 300,000,000 shares authorized at March 31, 2024 and December 31, 2023, respectively; 114,881,765 and 114,153,538 shares issued at March 31, 2024 and December 31, 2023, respectively; and 114,881,765 and 114,148,991 shares outstanding at March 31, 2024 and December 31, 2023, respectively	11	11
Additional paid-in capital	807,059	802,025
Accumulated other comprehensive loss	(138)	(62)
Accumulated deficit	(686,492)	(656,193)
Total stockholders’ equity	120,440	145,781
Total liabilities and stockholders’ equity	$ 144,143	190,796
Related Party
Current liabilities:
Amount due to related party		$ 739

Related Party Transactions

3 Months Ended

Mar. 31, 2024

Related Party Transactions

12. Related Party Transactions

In March 2020, the Company entered into a Management and Administrative Services Agreement with ElevateBio Technologies, Inc. that provides for ongoing services to the Company in areas such as information technology, human resources and administration management, and facilities. The Company is billed monthly for such services at cost, with mark-up for profit on specific services, but including reasonable allocations of employee benefits, facilities and other direct or fairly allocated indirect costs that relate to the associates providing the services. The agreement has an initial term of five years and will automatically renew for successive one year terms, unless earlier terminated under the terms of the agreement. In April 2024, the agreement was terminated effective May 1, 2024.

In May 2020, the Company entered into a Development and Manufacturing Services Agreement with ElevateBio BaseCamp, Inc. (“BaseCamp”) pursuant to which BaseCamp provides products and services that are used in the Company’s laboratory operations, including consulting services, project management services, quality control services and cGMP drug product manufacturing. The agreement will expire upon the later of (a) five years from the effective date of January 1, 2019 or (b) the completion of services under all work orders executed prior to the fifth anniversary of the effective date, unless earlier terminated under the terms of the agreement. All services under all work orders have been completed and the agreement expired on January 1, 2024.

The Company incurred $0.1 million and $0.2 million during the three months ended March 31, 2024 and 2023, respectively, related to services provided to the Company by ElevateBio and affiliates and sold $0.1 million of equipment to ElevateBio and affiliates during the three months ended March 31, 2024. At March 31, 2024 and December 31, 2023, the Company owed ElevateBio and affiliates $0 and $0.3 million, respectively, and had no prepaid expenses with ElevateBio and affiliates.

In March 2023, the Company entered into a services agreement with Marker Therapeutics, Inc. (“Marker”) pursuant to which Marker provides development services to the Company. Juan Vera, a current director and former executive officer of the Company, is co-founder, director and chief executive officer of Marker. In June 2023, CellReady LLC (“CellReady”) acquired certain manufacturing assets previously owned by Marker, and inherited the service agreement that Allovir previously maintained with Marker. The Company

incurred $0 during the three months ended March 31, 2024 and 2023, respectively, under the agreement. At March 31, 2024 and December 31, 2023, the Company owed CellReady $0 and $0.5 million, respectively.

Members of the Company’s management and board of directors received consulting fees totaling $0.1 million and $0.1 million during the three months ended March 31, 2024 and 2023, respectively.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

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+ Details

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at Dec. 31, 2022	$ 224,519	$ 9	$ 690,753	$ (468)	$ (465,775)
Balance, Shares at Dec. 31, 2022		93,093,243
Stock-based compensation	10,029		10,029
Issuance of common stock, upon vesting of restricted stock, Shares		334,747
Unrealized (loss) gain on available-for-sale securities	167			167
Net Income (Loss)	(41,183)				(41,183)
Balance at Mar. 31, 2023	193,532	$ 9	700,782	(301)	(506,958)
Balance, Shares at Mar. 31, 2023		93,427,990
Balance at Dec. 31, 2023	145,781	$ 11	802,025	(62)	(656,193)
Balance, Shares at Dec. 31, 2023		114,148,991
Stock-based compensation	5,034		5,034
Issuance of common stock, upon vesting of restricted stock, Shares		732,774
Unrealized (loss) gain on available-for-sale securities	(76)			(76)
Net Income (Loss)	(30,299)				(30,299)
Balance at Mar. 31, 2024	$ 120,440	$ 11	$ 807,059	$ (138)	$ (686,492)
Balance, Shares at Mar. 31, 2024		114,881,765

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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- Definition

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

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+ Details

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2024	May 06, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Trading Symbol	ALVR
Entity Registrant Name	ALLOVIR, INC.
Entity Central Index Key	0001754068
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		115,003,325
Security12b Title	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity File Number	001-39409
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	83-1971007
Entity Address Address Line1	1100 Winter Street
Entity Address City Or Town	Waltham
Entity Address State Or Province	MA
Entity Address Postal Zip Code	02451
City Area Code	617
Local Phone Number	433-2605
Document Quarterly Report	true
Document Transition Report	false

Related Party Transactions - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Consulting fees to members of management and board of directors	$ 100,000	$ 100,000
ElevateBio Technologies, Inc \| Management and Administrative Services Agreement
Related Party Transaction [Line Items]
Lease expiration term	The agreement has an initial term of five years and will automatically renew for successive one year terms, unless earlier terminated under the terms of the agreement.
BaseCamp \| DMS Agreement
Related Party Transaction [Line Items]
Lease expiration term	The agreement will expire upon the later of (a) five years from the effective date of January 1, 2019 or (b) the completion of services under all work orders executed prior to the fifth anniversary of the effective date, unless earlier terminated under the terms of the agreement.
ElevateBio and Affiliates
Related Party Transaction [Line Items]
Prepaid expenses	$ 0		$ 0
Expenses related to services with related party	100,000	200,000
Sale of equipment	100,000
Amount due to related party	0		300,000
Marker Therapeutics, Inc.
Related Party Transaction [Line Items]
Amount due to related party	0		$ 500,000
Costs incurred under agreement	$ 0	$ 0
Cost of Revenue, Related Party, Type [Extensible Enumeration]	Related Party [Member]	Related Party [Member]

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-based Compensation Expense

Stock-based compensation expense was as follows:


	Three Months Ended March 31,
(in thousands)	2024			2023
Research and development	$	(274	)	$	3,423
General and administrative		5,308			6,606
Total stock-based compensation expense	$	5,034		$	10,029

Summary of Restricted Common Stock Activity

The following table summarizes restricted common stock activity for the three months ended March 31, 2024:


	Shares			Weighted Average Grant Date Fair Value
Unvested at January 1, 2024		3,254,863		$	8.73
Granted		—			—
Forfeited		(957,148	)		8.13
Vested		(732,774	)		8.12
Unvested at March 31, 2024		1,564,941		$	9.37

Summary of Stock Option Activity

The following table summarizes stock option activity (in thousands, except share and per share data):


	Shares			Weighted Average Exercise Price		Weighted Average Contractual Life (in years)		Aggregate Intrinsic Value
Options outstanding at January 1, 2024		10,439,751		$	13.81		7.95	$	—
Granted		—			—		—		—
Exercised		—			—		—		—
Forfeited		(1,845,750	)		8.61		—		—
Options outstanding at March 31, 2024		8,594,001		$	14.93		7.54	$	—
Options vested and exercisable at March 31, 2024		5,972,960		$	16.44		7.29	$	—

Schedule of Estimated Fair Value Weighted-Average Assumptions Using Black-Scholes Option-Pricing Model

fair value was estimated on the date of grant using the Black-Scholes option-pricing model, with the following weighted-average assumptions:


	Three Months Ended March 31, 2023
Expected term (in years)		6.11
Expected volatility		94.50	%
Risk-free interest rate		3.46	%
Expected dividend yield	—
Fair value of common stock	$	6.63

Net Loss per Share - Potential Dilutive Securities Excluded From Computation Of Diluted Net Loss Per Share Attributable To Common Stockholders (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Options To Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	8,594,001	10,753,342
Unvested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	1,564,941	3,675,716

Net Loss per Share

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Net Loss per Share

10. Net Loss per Share

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company:


	Three Months Ended March 31,
(in thousands, except share and per share data)	2024			2023
Numerator:
Net loss – basic and diluted	$	(30,299	)	$	(41,183	)
Denominator:
Weighted-average common shares outstanding – basic and diluted		114,690,726			93,303,672
Net loss per share – basic and diluted	$	(0.26	)	$	(0.44	)


	March 31,
	2024		2023
Options to purchase common stock		8,594,001		10,753,342
Unvested restricted stock		1,564,941		3,675,716

Short-Term Investments (Tables)

3 Months Ended

Mar. 31, 2024

Investments, Debt and Equity Securities [Abstract]

Summary of Amortized Cost and Estimated Fair Value of Marketable Securities


	March 31, 2024
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. government treasury securities	$	54,495	$	4	$	(8	)	$	54,491
Totals	$	54,495	$	4	$	(8	)	$	54,491


	December 31, 2023
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. government treasury securities		93,749		73		—	$	93,822
Totals	$	93,749	$	73	$	—	$	93,822

- Definition

Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-9

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
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-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
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-Paragraph 2
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-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
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-Name Accounting Standards Codification
-Section 50
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-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

+ Details

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Cash equivalents:
Cash equivalents	$ 66,161	$ 23,854
Short-term investments:
Short-term investments	54,491	93,822
Money Market Fund
Cash equivalents:
Cash equivalents	66,161	23,854
U.S. Government Treasury Securities
Short-term investments:
Short-term investments	54,491	93,822
Level 1
Cash equivalents:
Cash equivalents	66,161	23,854
Short-term investments:
Short-term investments	54,491	93,822
Level 1 \| Money Market Fund
Cash equivalents:
Cash equivalents	66,161	23,854
Level 1 \| U.S. Government Treasury Securities
Short-term investments:
Short-term investments	$ 54,491	$ 93,822

Stockholder's Equity (Tables)

3 Months Ended

Mar. 31, 2024

Equity [Abstract]

Schedule of Reserved Shares of Common Stock for Issuance

The Company has reserved shares of common stock for issuance as follows:


	March 31, 2024		December 31, 2023
Options to purchase common stock		8,594,001		10,439,751
Unvested restricted stock		1,564,941		3,254,863
Stock available for grant under the 2020 Stock Option and Grant Plan		12,692,809		4,182,461
Stock available for issuance under the 2020 Employee Stock Purchase Plan	1,621,594			480,059
Total		22,851,751		18,357,134

Income Taxes

3 Months Ended

Mar. 31, 2024

Income Tax Disclosure [Abstract]

Income Taxes

9. Income Taxes

The Company’s income tax provision is computed based on the federal statutory rate, the average state statutory rates, net of the related federal benefit, and foreign statutory rates. For the three months ended March 31, 2024 and 2023, the Company did not record income tax expense due to the generation of net operating losses, the benefits of which have been fully reserved.

The Company’s estimate of the realizability of the deferred tax asset is dependent on estimates of projected future levels of taxable income. In consideration of historical losses and in analyzing future taxable income levels, the Company considered all evidence currently available, both positive and negative, and has not recognized deferred tax assets.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

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-Topic 235
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
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-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Name Accounting Standards Codification
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Employee compensation and benefits	$ 2,200	$ 3,809
Professional fees	464	435
Research and development	1,665	2,442
Process development and manufacturing costs		2,367
Other	267	1,033
Total accrued expenses	$ 4,596	$ 10,086

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par or stated value per share	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	114,881,765	114,153,538
Common stock, shares outstanding	114,881,765	114,148,991

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (30,299)	$ (41,183)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Stock-Based Compensation

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

8. Stock-Based Compensation

Stock-Based Compensation Expense

Stock-based compensation expense was as follows:


	Three Months Ended March 31,
(in thousands)	2024			2023
Research and development	$	(274	)	$	3,423
General and administrative		5,308			6,606
Total stock-based compensation expense	$	5,034		$	10,029

Stock Modification

In connection with the reduction in the Company’s workforce (“RIF”) (see Note 13), the Company accelerated certain unvested stock options and restricted common stock scheduled to vest in the three month period following the employees’ separation date. The Company determined that the acceleration of the unvested units constituted a Type III modification in accordance with ASC 718, resulting in a new measurement of compensation cost. As of March 31, 2024, 601,115 units were accelerated resulting in the recognition of $0.1 million of stock-based compensation expense using the reassessed fair value on the modification date and a reversal of $3.5 million in stock-based compensation expense for previously recognized expense using the original grant date fair value, of which $1.9

million was related to research and development expense and $1.6 million was related to general and administrative expense for the three months ended March 31, 2024.

2018 Equity Incentive Plan

At March 31, 2024, there was an aggregate of 64,042 shares of common stock issuable upon the exercise of outstanding options under the Company’s 2018 Equity Incentive Plan (the “2018 Plan”) and 6,616,772 shares of restricted common stock granted under the 2018 plan. No shares remain available for future issuance under the 2018 Plan. Any options or awards outstanding under the 2018 Plan remain outstanding and effective.

2020 Stock Option and Grant Plan

At March 31, 2024, there was an aggregate of 8,529,959 shares of common stock issuable upon the exercise of outstanding options under the Company’s 2020 Stock Option and Grant Plan (the “2020 Plan”) and 5,356,510 shares of restricted common stock granted under the 2020 Plan. There is an aggregate of 12,692,809 shares reserved for future issuance under the 2020 Plan.

Restricted Common Stock

The following table summarizes restricted common stock activity for the three months ended March 31, 2024:


	Shares			Weighted Average Grant Date Fair Value
Unvested at January 1, 2024		3,254,863		$	8.73
Granted		—			—
Forfeited		(957,148	)		8.13
Vested		(732,774	)		8.12
Unvested at March 31, 2024		1,564,941		$	9.37

At March 31, 2024, there was $12.3 million of unrecognized stock-based compensation expense related to restricted stock, which is expected to be recognized over a weighted average period of 1.90 years. The total fair value of restricted stock vested was $0.5 million and $1.6 million for the three months ended March 31, 2024 and 2023, respectively.

Stock Options

The following table summarizes stock option activity (in thousands, except share and per share data):


	Shares			Weighted Average Exercise Price		Weighted Average Contractual Life (in years)		Aggregate Intrinsic Value
Options outstanding at January 1, 2024		10,439,751		$	13.81		7.95	$	—
Granted		—			—		—		—
Exercised		—			—		—		—
Forfeited		(1,845,750	)		8.61		—		—
Options outstanding at March 31, 2024		8,594,001		$	14.93		7.54	$	—
Options vested and exercisable at March 31, 2024		5,972,960		$	16.44		7.29	$	—

The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the common stock as of the end of the period.

There were no options granted during the three months ended March 31, 2024. The weighted-average grant date fair value of stock options granted during the three months ended March 31, 2023 was $5.18 per share. At March 31, 2024, there was $19.4 million of unrecognized stock-based compensation expense related to unvested stock options, which is being recognized over a period of 1.63 years.

There were no options granted during the three months ended March 31, 2024. For the three months ended March 31, 2023, the fair value was estimated on the date of grant using the Black-Scholes option-pricing model, with the following weighted-average assumptions:


	Three Months Ended March 31, 2023
Expected term (in years)		6.11
Expected volatility		94.50	%
Risk-free interest rate		3.46	%
Expected dividend yield	—
Fair value of common stock	$	6.63

2020 Employee Stock Purchase Plan

The Company did not issue common shares under the Employee Stock Purchase Plan (the “ESPP”) during the three months ended March 31, 2024. The Company recognized $0.0 and $0.1 million of compensation expense for the ESPP during the three months ended March 31, 2024 and 2023, respectively.

At March 31, 2024, there was an aggregate of 1,621,594 shares reserved for future issuance under the ESPP.

Stockholders Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 21, 2023	Mar. 31, 2024	Dec. 31, 2023	May 15, 2023
Class Of Stock [Line Items]
Preferred stock, par or stated value per share		$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized		10,000,000	10,000,000	10,000,000
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common stock, shares authorized		300,000,000	300,000,000	300,000,000
Common stock, par value		$ 0.0001	$ 0.0001	$ 0.0001
Underwriter \| J.P. Morgan Securities LLC [Member]
Class Of Stock [Line Items]
Stock issued	20,000,000
Offering price per share	$ 3.75
Proceeds from issuance of common stock	$ 70.2
Underwriting discounts commissions	4.5
Offering costs	$ 0.3
Option to purchase additional number of shares	3,000,000
Expiration of option to purchase additional number of shares	Jul. 21, 2023